Vasoconstrictor substance

An increase in MAP leads to an increase in RBF, PGC/ and GFR. As a result, the rate of fluid flow through the distal tubule increases, leading to an increase in reabsorption of Na+ and Cl ions by the cells of the macula densa in the distal tubule. Consequently, these cells release vasoconstrictor substances, primarily adenosine. The subsequent increase in the resistance of the nearby afferent arteriole decreases RBF to normal and, as a result, PGC and therefore GFR decrease to normal. In this way, the distal tubule regulates its own filtrate flow. 

Vasoconstrictor substances such as epinephrine reduce systemic absorption of local anesthetics from the injection site by decreasing blood flow in these areas. This is important for drugs with intermediate or short durations of action such as procaine, lidocaine, and mepivacaine (but not prilocaine). 

A second peptide is pepsitensin, formed by peptic digestion of the substrate of renin (13). It represents an interesting type reaction similar to that of renin. Because two proteolytic enzymes, renin and pepsin, act on a protein to produce vasoconstrictor substances, the substrate must have peculiar structural properties conducive to formation of these substances when broken down. The pharmacology of pepsitensin has not been ex-... 

Thromboxane A2 (TxA2) is an exceptionally potent pro-aggregatory and vasoconstrictor substance produced by the metabolism of arachidonic acid in blood... 

Endothelial cells and the kidneys play probably an important role in the longterm homeostasis as well as in the development of AD. Endothelial cells synthesize and release vasorelaxant and vasoconstrictor substances. The vasoconstrictor mediators, endothelins, were isolated, purified, sequenced, and cloned [100], The human endothelin receptor has seven membrane helices and is apparently G-protein-coupled. Endothelin-induced smooth muscle contraction involves the following processes activation of PLC, PIP2 hydrolysis, generation of 1,4,5-IP3, accumulation of DAG, mobilization of intracellular Ca2+ with facilitation of Ca2+ influx, activation of PKC, activation of PLA2 and arachidonic acid release, activation of PLD, and stimulation of Na+-H+... 

Vascular haemostasis comprises reflex contractions of the arteries, reinforced by the release of vasoconstrictor substances from the vessel walls (e.g. catecholamines, serotonin, thromboxane A2). 

O Brien RF, Robbins RJ, McMurtry IF. Endothelial cells In culture produce a vasoconstrictor substance. J Cell Physiol 1987 132 263-270. 

Meanwhile Rapport and his colleagues had been investigating the vasoconstrictor substance in serum which they named serotonin, and isolated in 1948 (693, 694). The isolated material was shown (692) to be a complex of creatinine with what was thought to be 5-hydroxytryptamine (structure diagram 23) and identification of the latter was confirmed by synthesis (19, 341, 363, 821). It then became clear that enteramine and serotonin were identical (e.g., 238, 239), and an enormous amount of work on the physiology and pharmacology of 5-hydroxytryptamine has subsequently appeared (reviews 235a, 237, 660, 958). 

Vasodilator Vasoconstrictor substances which have the property of dilating or constricting veins. Vermifuge substance which causes the expulsion of worms. 

Spector and Willoughby - have pointed out that the vascular changes in the acute inflammatory reaction may be due to the destruction of local vasoconstrictor substances such as adrenaline. Evidence in favour of this mechanism includes the observation that increased capillary permeability after thermal injury is suppressed by iproniazid and other monoamine oxidase inhibitors. Such inhibitors are known to inhibit the conversion of adrenaline, noradrenaline, 5-hydroxytryptamine and other amines to inactive metabolites. The authors provide evidence that the action of the monoamine oxidase inhibitors on capillary permeability is dependent on their anti-enzymic activity and not on some other unrelated property. Nevertheless, the evidence remains indirect an attempt to detect pressor amines in the plasma of burned animals was unsuccessful. The potentiating effect of bretylium and the antagonistic action of an adrenolytic substance, dibenamine, on the action of iproniazid suggest that it is local depots of adrenaline rather than noradrenaline or 5-hydroxytryptamine which are involved. Independent support for this suggested role of catecholamines... 

As long ago as the middle of the nineteenth century, physiologists were aware that blood serum contained a vasoconstrictor substance, but this material ( vasotonin or serotonin ) was not isolated in a pure form until 1948 . Rapport shortly afterwards identified serotonin as 5-hydroxytryptamine . A few years later Erspamer demonstrated that enteramine , an active material he had detected in extracts of intestinal mucosa almost 20 years earlier, was also 5-hydroxytryptamine . Subsequently, 5-hydroxytryptamine was found to be widely distributed in tissues and to possess a... 

This substance has been shown to reduce the incidence of stroke and infarction, due to its vasodilatory actions. In animals, it has been shown to alter the lipid profile of cardiac myocytes and reduce the production of inositol triphosphate (a vasoconstrictor substance). 

Which of the following is a decapeptide precursor of a vasoconstrictor substance ... 

The hepatorenal syndrome is characterized by acute renal failure in the setting of advanced cirrhosis, sometimes with ascites. The diminution in renal function is felt to be due to marked vasoconstriction without any structural abnormality. A variety of vasoconstrictor substances have been implicated,... 

The potent vasodilatory effects of PGE, have been used with success in treatment of severe forms of Raynaud s disease as well as vascular insufficiency in systemic sclerosis and other connective tissue diseases [168], PGE, and PGE2 also relax the ductus arteriosus of newborns. Infusions of PGE, (50 ng/kg/min) to newborns with certain cardiac malformations, which make the persistence of the ductus essential for the systemic or pulmonary circulation, improves the clinical condition and allows surgery to be delayed to a more suitable time (see ref. 169 for a review). The tone of the ductus arteriosus seems to be balanced between the constrictor effects of oxygen, possibly also other vasoconstrictor substances, and the dilatory effects of prostaglandins formed intramurally [170], Inhibitors of prostaglandin biosynthesis have been used to induce closure of patent ductus arteriosus of newborns, and in most cases the conventional surgical treatment could be omitted [171], For reviews on the role of prostaglandins in the vascular system see refs. 133, 165, 172 and 173. 

A vasoconstrictor substance present in serum had long been known as serotonin . In 1948, Rapport and his group finally isolated this from beef serum as a creatinine sulphate complex of 5-hydroxytryptamine. 

As mentioned previously (page 64), Spector and Willoughby have suggested that some of the vascular phenomena occurring in tissue injury may be the result of the local destruction of adrenaline-like vasoconstrictor compounds. They measured increased capillary permeability in rats subjected to thermal injury and turpentine-induced pleurisy. The subcutaneous administration of five monoamine oxidase inhibitors, including iproniazid, markedly inhibits both types of inflammation. Iproniazid inhibition can be completely antagonized by the intravenous injection of the adrenolytic substance, dibenamine, but not by adrenalectomy. A subcutaneous dose of 0-5 mg/kg of adrenaline also reduces capillary permeability, but noradrenaline even in doses of 1 mg/kg is ineffective. From this and other evidence they conclude that in tissue injury, apart from the release of substances increasing capillary permeability, there is the release of an adrenaline-like vasoconstrictor substance which is itself destroyed by monoamine oxidase. 

Vascular Resistance - The major hemodynamic abnormality in hypertensive patients and laboratory animals is an elevated peripheral vascular re sistance. Suggested etlologlc factors which may contribute to the increased vascular resistance are enhanced humoral vasoconstrictor substances, decreased humoral vasodilator substances, enhanced neurogenic vasoconstrictor activity, expanded extracellular fluid volume, "auto-... 

These results suggest that renin is an enzyme-like substance which is activated by a kinase-like material contained in the protein fraction of plasma and whole blood. And later they (107) wrote These experiments. .. therefore suggest that either whole blood, plasma, or filtrate of laked erythrocytes activates the vasoconstrictor action of renin, or that a latent vasoconstrictor substance in blood is activated by renin. ... 

If hypertensin is the vasoconstrictor substance in hypertension, it should be possible to lower blood pressure by the administration of hyper-tensinase. Several investigators (96,129,130) reported favorable results... 

The circulatory status of patients with essential hypertension resembles fundamentally the hypertension produced in animals. There is also clinical evidence that the kidneys are diseased in many patients with hypertension. Fishberg (45) and Bell and Clawson (10), as well as Moritz and Oldt (115), have found oi anic arteriolar disease in the kidneys of a majority of patients who had essential hypertension with or without signs of disturbed renal excretory function. Furthermore, renal ischemia was found to be present in many hypertensive patients (169). This ischemia seemed to be the result of the presence of vasoconstrictor substances in the blood, since it was readily reversible by agents which produce renal hyperemia in normal persons. Smith, Goldring, and Chasis (169) investigated the impairment of renal blood flow in 21 hypertensive patients. In none of these patients did the authors find unilateral impairment of the renal blood flow. 

Clotted blood releases an array of cerebral vasoconstrictor substances. 

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